1. Field of the Invention
The present invention relates to an image forming apparatus, such as a copier, a printer, and/or a facsimile, and in particular to an image forming apparatus having a cleaning member configured to clean a transparent member of an optical device included in the image forming apparatus.
2. Description of the Related Art
In image forming apparatuses, such as a laser printer and a copier, laser light is applied to photoconductive drums, or photosensitive member, in accordance with image signals, causing electrostatic latent images to form on photoconductive drums. The electrostatic latent images are developed with toner, whereby the electrostatic latent images are visualized. Such an image forming apparatus has a casing having an openable/closable cover so that the laser light does not leak outside while the apparatus is under operation.
When replacing process cartridges with new ones, removing a jammed sheet during an operation, or performing a maintenance operation, the openable/closable cover is opened while the main power remains on. Particularly, where laser light is used in the apparatus, it is important to prevent the laser light from leaking outside of the apparatus when the cover is open, even in case of malfunction of an interlocking switch.
The image forming apparatus includes a laser shutter. The laser shutter is provided on an optical scanner or inside the image forming apparatus including the optical scanner, and is configured to operate in conjunction with the attachment and removal of a process cartridge, including a photoconductive drum, and the opening and closing of the cover of the casing of the apparatus. Specifically, when a user or a serviceman opens the cover of the image forming apparatus to attach or remove a process cartridge or to remove a jammed sheet, for example, the laser shutter blocks the optical path of the laser light, thereby preventing the user or the serviceman from being exposed to the laser light.
Japanese Patent Laid-Open No. 11-337859 discloses an exemplary configuration in which a laser shutter is turned in conjunction with the opening and closing of an openable/closable cover when a process cartridge is attached and removed and when a jammed sheet is removed, whereby the laser shutter blocks the optical path of laser light traveling toward a redirecting mirror.
In recent electrophotographic image forming apparatuses using toner as developing material, the toner is often scattered, resulting in dust inside the image forming apparatus. Laser scanners, as exposure units included in such image forming apparatuses, are sensitive to dust, including toner. Therefore, the interior of such a laser scanner is sealed so as to prevent toner and dust from entering thereinside.
The image forming apparatus has an opening through which laser light emitted from the laser scanner passes. To prevent toner and dust from entering the interior of the laser scanner through the opening, a cover glass that allows the laser light to pass therethrough is provided over the opening.
In such a configuration, toner and dust falling from a developing unit in the process cartridge and straying inside a main body of the apparatus may enter the optical path of the laser light and adhere to the cover glass, thereby blocking the optical path. This causes a reduction in the density of a printed image or a missing portion in a printed image. To prevent the reduction in the image density and the occurrence of a missing portion in an image, the image forming apparatus needs to be configured such that toner and dust do not adhere to the cover glass, or such that toner and dust adhered to the cover glass can be removed.
Therefore, a user or a serviceman accesses the interior of the image forming apparatus and wipes the cover glass clean with a soft cloth or the like. However, it is very difficult to thoroughly clean the cover glass, which has only a small surface area, without damaging the surface.
Japanese Patent Laid-Open No. 2005-246901 discloses a cleaning technique of removing toner and dust adhered to a dust-proof glass. Specifically, a cleaning member is slid along the dust-proof glass by a user or a serviceman, whereby toner and dust adhered to the dust-proof glass is removed.
In recent tandem color image forming apparatuses having small sizes and discharging sheets at increasingly high speeds, it is preferred that major components required for image forming are configured and arranged as a small assembly. In particular, a tandem color image forming apparatus, which includes a plurality of photoconductive drums and uses a plurality of laser beams, requires a plurality of image forming units for respective colors. Under such circumstances, it is preferable to design the image forming units as compact as possible.
The tandem color image forming apparatus naturally requires a plurality of laser shutters for protecting the user from the laser beams, resulting in configurational complexity. To provide a laser shutter mechanism, space is necessary between the photoconductive drum and the laser scanner. This reduces the flexibility in arrangement of the components to be included in the image forming area, hindering the size reduction of the apparatus.
Also in the technique of cleaning the dust-proof glass by using a slidable cleaning member disclosed in Japanese Patent Laid-Open No. 2005-246901, a guide member along which the cleaning member is provided separately. This increases the number of components and requires additional space to accommodate the guide member.